Multimeter

[neabd90]

I have an Eagle Analogue multimeter which was not used for a long time. I have fitted new batteries but nothing works. Can’t find a fuse. Can you help?

 

[JimB]

A few more details would be useful.
Is it a simple multimeter?
Does it have an amplifier inside, as in a "Valve Voltmeter"? (Please excuse the 50 year old expression!).

Any chance of a few pictures?

JimB

 

[gophert]

I have an Eagle Analogue multimeter which was not used for a long time. I have fitted new batteries but nothing works. Can’t find a fuse. Can you help?

Your test leads may be damaged. since it is an old analog meter without any distinguishing technical merit, i would take a trip to the hardware store, buy a new ($15) digital multimeter and throw the Eagle meter in the dust bin. Not worth your time or ours to diagnose or repair. Not even worth buying the fuse as a test.

 

[neabd90]

It is a simple meter possibly from the 70’s. No amplifier or fuse. Test leads are ok. I have two digital meters already. I would just like the challenge of repairing this. Hope this helps.

Hi

 

[neabd90]

New photos

 

[neabd90]

New photos

 

[neabd90]

New photos

 

[gophert]

Well, it looks like you MAY have changed the 1.5V AA battery recently but the 15V Alkaline battery looks original and needs to be changed. You can look for a A220 or 504A in a vintage camera shop. No idea if their batteries will be dead from sitting on the shelf so long. Rare battery these days.

It also looks like the potentiometer "A" in photo below was changed and poorly soldered.

Also, diode at "B" looks a bit hokey - are you the original owner or did someone hack it to adjust a range or repair an over-current issue in its past? Same is possible for the weirdly placed resistor at "C".

Also, the coil at "D" looks like it may be burnt or corroded and it may be shorting out the trace on the perimeter of the pcb.

I'd say "Good luck" but I am guessing your wife will soon appreciate that you have one less piece of crap laying around the house when it falls into the bin.

 

[Nigel Goodwin]

I would disagree with gophert, it all looks original, apart from the batteries - both of which have been replaced - you didn't get Alkaline batteries when this meter was made.

As far as batteries go, they only have any effect on ohms ranges, on volts or amps it works perfectly with no batteries fitted, which is quite handy as you can use such a meter to test it's own batteries (with them removed).

 

[schmitt trigger]

The very first thing that requires to be cheked is that the analog movement works or not.
With your DMMs set in ohms, briefly touch the movement terminals to see if it moves.

 

[dr pepper]

Having 2 batteries, one of them 15v makes me wonder if its a fet input meter, but theres no sign of that on the board.
If you gently wiggle the meter does the pointer move?
A while back I was given an insulation tester with a moving coil meter like this, I thought I could easily fix it, but then I found the meter movement was open circuit.

 

[Nigel Goodwin]

Having 2 batteries, one of them 15v makes me wonder if its a fet input meter, but theres no sign of that on the board.

You're obviously far younger than I thought

The 15V battery is for the high ohms range, you can't do a high ohms range with a 1.5V battery.

The meter is also clearly labelled on the front 30,000 ohms per volt, typical (and top end) for an analogue meter, most are either 20K or 30K, with some cheaper ones only 10K. If it was an FET based meter, it would most likely be 10Mohms across all ranges just like a digital meter.

 

[schmitt trigger]

And of course, if one is still a tiny little bit older....one would be talking VTVMs.

 

[Nigel Goodwin]

And of course, if one is still a tiny little bit older....one would be talking VTVMs.

Not really, simple passive multimeters were about long before VTVM's.

 

[schmitt trigger]

I know that....
my comment was that, us older geezers in this forum, actually worked with something made out of glass, prior to using transistors.
In the case of high-end, high-impedance meters, the meters used valves (vacuum tubes).

 

[Nigel Goodwin]

I know that....
my comment was that, us older geezers in this forum, actually worked with something made out of glass, prior to using transistors.

As did I, not that I've ever owned or used a VTVM though.

 

[chemelec]

I Still have One, (Hewitt Packard) not that I use it very often.

 

[schmitt trigger]

I never could afford to own a VTVM...way too expensive for my student budget.
But I would salivate at the thought of actually being capable of taking a DC bias reading without affecting the actual measurement.

Later, when I started working and could afford something better than my plain 20kohm/v meter, FETVMs had already become affordable, and I bought one of them.

 

[dr pepper]

I must be younger than you thought Nige, not pushed 50 yet.
Missed the 30k per volt.
My first meter was analogue, and I think I had an eagle one at one time, wasnt eagle a brand owned by altai?
I have a stash of tubes, and a few radio's, no Vtvm, just an analogue fet meter!

 

[Nigel Goodwin]

My first meter was analogue, and I think I had an eagle one at one time, wasnt eagle a brand owned by altai?

I'm not sure, they did similar ranges, but Eagle always seemed the slightly better brand.